JPH045017Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The invention detects the current flowing through the circuit without disconnecting the electrical wiring circuit of a car and connecting a resistor, for example, to disconnect the lighting lamp. The present invention relates to a current detection device that detects the following.

[Prior Art] Conventionally, this type of current detection device has a slit in a part of the ferrite core 1 which is closed in the form of a magnetic circuit, such as a ring, as shown in FIG. An electric wire 3 of the circuit for which current is to be detected is passed through the hole in the center of the annular ferrite core 1. By doing this, a current flows through the electric wire 3. As a result, a magnetic field is generated in the ferrite core 1, and an output proportional to the strength of the magnetic field is obtained in the magnetic sensing element 2. The detection principle is as described above, but in practice, it is difficult to pass the electric wire 3 through the closed ferrite core 1, so the ferrite core 1 is doubled as shown by 1a in the figure. It is often manufactured in parts, and then fixed with adhesive or the like after passing the electric wire 3 through it.

[Problems to be solved by the invention] However, although the conventional current detection methods described above are generically called one-turn type,
In reality, the magnetic field caused by the current acts on the ferrite core for only 1/4 turn, and since the number of turns (turns) of the wire around the ferrite core is small, the detection sensitivity is very low.
A problem has arisen in that it is difficult to integrate the ferrite cores made by dividing them into one piece by gluing or the like on an automobile assembly line or the like. Furthermore, in any case, the ferrite core must be attached and fixed by some method.

[Means for Solving the Problems] The present invention provides a ferrite core having a closed magnetic circuit and a sensor provided in the magnetic circuit as a specific means for solving the above-mentioned conventional problems. In a current detection device comprising a magnetic element, a metal fitting is provided that straddles the ferrite core at one or more positions, is connected to a conductive pattern arranged on the printed circuit board surface at both ends, and fixes the ferrite core in a fixed position. By providing a current detection device characterized in that the metal fitting serves both as a support for the ferrite core and as a flow path for the current to be detected, the current detection sensitivity can be made high, and the problem of installation can be solved at the same time. It is something to be solved.

[Example] Next, the present invention will be explained in detail based on an example shown in the drawings. In order to facilitate understanding, the same parts as in the conventional example will be described with the same reference numerals.

What is indicated by the symbol 1 in FIG. 1 is a ferrite core similar to the conventional example, and the magnetic sensing element 2 is similar to the conventional example.
However, unlike the conventional example, it is fixed to the printed circuit board 5 by a metal fitting 4. Said metal fitting 4
serves both as a purpose of fixing the ferrite core 1 to the printed circuit board 5 and as an electric circuit for passing the current to be detected, and has a shape suitable for fixing, such as a U-shape, so as to meet both purposes.
In addition, it has a cross-sectional area sufficient to allow the current to be detected to flow, and is made of a metal such as copper that has excellent electrical conductivity. The metal fitting 4 formed as described above is soldered to the pads 6a and 6b, which are conductive patterns provided on the printed circuit board 5, so that the ferrite core 1 is straddled over the ferrite core. 1 and the metal fitting 4 are fixed to the printed circuit board 5 at the same time. At this time, the pads 6a and 6b are appropriately extended to form terminal portions, so that each of the terminal portions is fixed to the printed circuit board 5. By cutting the shown electric wire 3 and performing soldering or terminal connection, an equivalent circuit corresponding to FIG. 2 is obtained.

The above explanation has been made for the case where there is only one metal fitting 4 in order to show the most basic principle, but in this type of installation, two or more metal fittings are usually provided, so approximately An increase in sensitivity of more than double can be expected.

In FIG. 3, there are four metal fittings 4a to 4b,
Along with this, the number of parts 6a to 6e is increased to five locations, and in this case, 6a to 6d of the parts are arranged so that they also serve as current coils together with the metal fittings 4a to 4d. It was devised.

In addition, in FIGS. 1 and 3, insulation treatment is naturally performed between the ferrite core 1 and the metal fittings 4, 4a to 4d.

[Effects of the invention] As explained above, according to the present invention, a metal fitting is provided that straddles the ferrite core, and the metal fitting serves both for fixing the ferrite core and as a current circuit, so that the metal fitting has a U-shape, etc. By having a shape suitable for mounting and surrounding the ferrite core on three sides, the electrically acting surface of the metal fitting on the ferrite core is three sides, that is, a 3/4 turn, and one side of the conventional case, that is, a 1/4 turn. The detection sensitivity is increased by about 3 times even with a single metal fitting compared to the previous one, and it is also possible to further increase the sensitivity by adding more metal fittings, and in any case, there are no mounting metal fittings that would otherwise be required. Furthermore, this current detecting device can be assembled into an automobile by simple operations such as soldering or terminals, thereby increasing the practicality of the current detecting device.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing one embodiment of the current detection device according to the present invention, Fig. 2 is an explanatory diagram showing an electrical equivalent of Fig. 1, and Fig. 3 is another embodiment of the same invention. 4 is an explanatory diagram showing an electrical equivalent of FIG. 3, and FIG. 5 is a perspective view showing a conventional example. 1... Ferrite core, 2... Magnetic sensing element, 3...
...Electric wire, 4,4a-4d...Metal fittings, 5...Printed circuit board, 6a-6e...Puts.

Claims (1)

[Scope of utility model registration request] In a current detection circuit comprising a ferrite core having a closed magnetic circuit and a magnetic sensing element provided in the magnetic circuit, the ferrite core is arranged on a printed circuit board, and the ferrite core is connected to the ferrite core at one or more positions. A metal fitting is provided that extends over the ferrite core and is connected at both ends to a conductive pattern arranged on the printed circuit board surface and fixes the ferrite core in a fixed position, and the metal fitting supports the ferrite core and provides a flow path for the current to be detected. A current detection device that doubles as a current detection device.